The invention relates generally to semiconductor devices and integrated circuit fabrication and, in particular, to assemblies including a device layer of a semiconductor-on-insulator (SOI) substrate and a replacement substrate replacing a handle wafer of the SOI substrate, and to methods for transferring the device layer of the SOI substrate from the handle wafer of the SOI substrate to the replacement substrate.
Devices fabricated using semiconductor-on-insulator technologies may exhibit certain performance improvements in comparison with comparable devices built directly in a bulk silicon substrate. Generally, an SOI wafer includes a thin device layer of semiconductor material, a handle wafer, and a thin buried insulator layer, such as a buried oxide or BOX layer, physically separating and electrically isolating the device layer from the handle wafer. Integrated circuits may be fabricated using the semiconductor material of the device layer at the front side surface of the SOI wafer and possibly the semiconductor material of the handle wafer.
Wafer thinning has been driven by the need to make packages thinner to accommodate stacking and high density packaging of chips. An SOI wafer may be thinned by removing the handle wafer from its construction and, once thinned, subjecting the backside surface to additional operations. To lend mechanical support during thinning and any additional operations performed after thinning, the front side surface may be adhesively bonded to a temporary substrate. After the additional operations are performed, a permanent substrate may be attached to the backside surface as a replacement for the handle wafer and the temporary substrate may be removed from the front side surface.
Improved assemblies including a device layer of an SOI substrate and a replacement substrate for a handle wafer of the SOI substrate, and improved methods for transferring a device layer of the SOI substrate from the handle wafer to a replacement substrate are needed.